<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="UTF-8" />
		<meta http-equiv="X-UA-Compatible" content="IE=edge" />
		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
		<title>typeOf</title>
	</head>
	<body>
		<script>
            //typeof：能判断所有值类型，函数。不可对 null、对象、数组进行精确判断，因为都返回 object
			// console.log(typeof undefined) // undefined
			// console.log(typeof 2) // number
			// console.log(typeof true) // boolean
			// console.log(typeof 'str') // string
			// console.log(typeof Symbol('foo')) // symbol
			// console.log(typeof 2172141653n) // bigint
			// console.log(typeof function () {}) // function
			// // 不能判别
			// console.log(typeof []) // object
			// console.log(typeof {}) // object
			// console.log(typeof null) // object
		</script>
	</body>
</html>
